I'm still fairly new to the forum, but thought i'd share some insight from having 30 years in the metal finishing industry. Although I do not do my own plating, I have worked with several plating shops over the years to provide premium grade decorative chrome and high tech nickel and gold to the semiconductor industry. Established vendor relationships are everything. Before you go sending your wheels off to the "chrome shop", there are some things to consider.
9 out of 10 times, 4-6 weeks turnaround will turn into 12.
Plating in a job shop fashion is much different than having a dedicated plating line that is used in production by the large manufacturers. Many parts aren't that critical, but the shape,size and material of these wheels make it more important that several factors be in place. In order to do justice to these rims, the shop needs detail polishing capabilities in order to polish and blend the recessed areas between the spokes.
Since these wheels already have a coating from the factory, the first step is to strip this coating off. Many shops will etch the base metal in the process. This can be controlled as long as the person doing the stripping is paying attention, they know what alloy the wheels are made of, and have the proper stripping chemicals that are in optimum condition.
The wheels then need to be detail polished so that they are shiny in between the spokes as well as the face, otherwise they will look frosted when plated. In a production setting, there is no stripping involved since fresh material is being used. Most often a polishing station will be designed and dedicated to doing the particular shapes of the wheels, whether by an individual with power hand tools sized for the job, or by semi-automatic or fully automatic machine stations.
Next starts the plating process. With brass and steel it isn't as critical to have the chemcals in optimum condition, but it doesn't take much variance in chemical conditon to cause problems plating aluminum. With EPA regs and cost of handling and disposal of plating solutions, many shops run their tanks on the ragged edge to get the most out of them. If the shop just ran a bunch of iron pipe that still had cutting oil from the machine shop, or some other similar scenario, the filters in their tanks would not have enough time to purge the contaminants which in turn would end up on your wheels.
The most sensitive parts(like our wheels) sometimes end up being the indicator of when the chemicals are on the edge of no longer working properly. Bad adhesion in the form of blistering bubbles to peeling off in a sheet can result. It is at this point that some shops start the finger pointing and tell you that the metal is bad and give you your part back. Problems in the metal can occur since some of the alloys are not totally homogenous, but it is the exception, not the rule.
Next is the issue of coverage. Plating is deposited by electrical current going thru the bath and on to the part, kind of like lightning. It hits the high points first, then the valleys. On a part with recesses, it is difficult to get the nickel and chrome to throw into the recesses without burning the high spots. It is the skill of the plater to know the condition of the baths and how much electrical current to use and for how long in order to get the best coverage. This is difficult in a job shop setting where there is no learning curve. A plater I worked with many years ago that did the plating exclusively for Zenith Wire Wheels, made special fixtures and anodes to "throw" the plating down into the recesses in order to reduce what is called "nickel shadow" or "yellowing". I presume that the large wheel mfg'rs are doing the same.
The next issue has to do with liability if something goes wrong. A reaction called "hydrogen embrittlement" takes place in the chrome plating process. This may or may not be an issue on parts of this thickness, but this is why springs and torsion bars are never chromed, because they become very brittle and will snap much like an uncooked strand of pasta. This can be reversed to a great degree by a baking process to restore the original metal qualities, but some knowledge of metallurgy is required. There has been some comments posted about concern over the strength of these wheels. If your wheel broke after they were modified in this way by your vendor, you would not have the legal recourse that you would have if you purchased the wheel outright.
Long story Long, you would eliminate the down time, the risk, know what you were getting before you bought it, and have your original wheels intact as backup for probably the same or better price. $900.00, including shipping would scare me without seeing their work in advance and references from someone that had this particular part done by them.
So what are viable options?
1.Removing the coating and just polishing the aluminum. Unfortunately, this will be an even higher maintenance option requiring hand polishing, but will look nice.
2.Black Chrome shares the same issues as hexavalent chrome, harder to plate
less durable, few shops do it, those that do may not have a tank large enough for wheels like this.
3. Powder coating is a good alternative if you can get a color and texture that you like.
4.Purchase wheels already plated like some of the knockoffs on EBAY- this option solves the problem of dealing with platers and focuses liability on the manufacturer, but still leaves you subject to not knowing what alloy or heat treatment(if applicable)is used -SCARY
5.Aftermarket wheels - other mfr's.
I know that I've given a whole lot more info than you asked for, but I hope shedding some light on the processes was some help to you or other readers.
P.S. Krylon anyone?